In the third and final part of our series on doping, we present the main substances and methods banned in sports. Most of the banned substances appear on the World Anti-Doping Agency's 2004 Prohibited List, but a leading expert also speaks about the new, difficult-to-detect substances called designer steroids.

(Eds: This can run with today's DD-21, Doping, Part 2: 'Muscle Mania' Poses Risk of Steroids Abuse Among Youths, and yesterday's DD-26, Doping, Part 1: Performance-Enhancing Drugs a Threat to Health -- and Ethics, by Eugen Tomiuc.)

Prague, 25 March 2004 (RFE/RL) -- Anabolic steroids are among the main items appearing on a list of prohibited substances that is part of the new Anti-Doping Code.

The Anti-Doping Code will be enforced by the International Olympic Committee -- the supreme authority of the international Olympic movement -- at the Games in Athens from 13-29 August.

Dr. Hans Geyer is deputy director of the Cologne Doping Control Laboratory in Germany, one of the world's leading antidoping institutes. He explains what anabolic steroids are: "Anabolic androgenic steroids consist of substances which are similar to endogenous [natural] steroids like testosterone, or dihydrotestosterone (DHT), and consist of substances of synthetic androgenic steroids. Anabolic androgenic steroids are used mainly to enhance muscle mass performance over the training effect, and with these substances we have most positive cases worldwide in the doping control laboratories."

"So-called designer steroids have been illicitly developed for athletes with the aims of enhancing performance and avoiding detection."

Naturally produced testosterone is also banned, because it is used in doping and is more difficult to detect than synthetic steroids.

Male hormones have two different effects on the body -- an anabolic effect, which stimulates growth, and an androgenic effect, which increases male sexual characteristics.

Synthetic steroids, which are artificial hormones, have been designed to maximize the anabolic effect and minimize the androgenic effect.

In their natural state, steroids are molecules that act as messengers. The most important message steroids deliver to the body is to increase the synthesis of protein and creatine phosphate.

Creatine phosphate is an organic compound found in the muscles, where its hydrolysis releases energy for muscular contraction. An increased amount of creatine allows for harder muscular training.

Anabolic steroids are normally used to treat a variety of illnesses and injuries, from tendon injuries to vision problems.

Testosterone was first synthesized in the 1930s by the Germans, while the first anabolic steroids appeared in the late 1950s.

Dr. Geyer explains what the main steroid types are and how they are taken: "Anabolic steroids mainly used by athletes are the oral preparations of metandienone, stanozolol -- that's the product that we found, for instance, in [1988 at the Seoul Olympics in Canadian athlete] Ben Johnson's urine. Other substances are testosterone and nandrolone -- these substances are mainly injected. And another oral preparation which is now very famous is the THG, the tetrahydrogestrinon -- this is a new designer drug."

Unlike other anabolic steroids, which were created primarily to cure illnesses, so-called designer steroids have been illicitly developed for athletes with the aims of enhancing performance and avoiding detection.

Dr. Geyer explains why they are more dangerous than other steroids: "Designer steroids are steroids which are specially prepared for the sports market, and THG is, I think, the first one which we have detected. Designer steroids have never been approved on the official market, and the performance-enhancing effects of these drugs -- their toxicity and the side effects -- have never been tested. So it's really a risk to use such drugs, and we wonder why athletes take such risks."

Peptide hormones make another category of banned substances on the World Anti-Doping Agency's (WADA) list. Among them are human growth hormones, or hGH, and erythropoietin, or EPO.

Dr. Geyer says there are no scientific reports on the performance-enhancing effects of hGH. He says many hGHs on the market are fake and do not contain human growth hormones at all. Others are old and dangerous products from former Soviet stocks, as he explains: "Old products from the former Soviet Union are sold on the European market, and these old products contain human growth hormone extracts of the hypophisis [gland], so I think this is very dangerous because these extracts are connected with the [variant] Creutzfeldt-Jakob disease, and it has severe side effects."

The enhancement of oxygen transfer, or blood doping, is also among the prohibited methods on the WADA list. It involves blood transfusions and the use of artificial blood.

Geyer says blood transfusions are hazardous for two reasons: "The blood transfusions are dangerous because the transfusion itself is connected with AIDS, for example, and with other types of infections from the transfusion, and then because the viscosity of the blood is increased, so maybe special problems of the blood flow can occur which may cause blood clots."

Stories circulated during the 1998 Tour de France doping scandal of riders who were using erythropoietin (EPO) being woken up in the middle of the night to walk around to prevent blood clots from forming.

But Geyer says that, currently, efficient methods have been developed to detect both the use of artificial blood and erythropoietin: "What is also being done in this field is that, for example, the injection of bovine hemoglobin, or artificial blood, has the same effect as blood transfusions. It increases the oxygen transport capacity of the blood and, therefore, it increases the endurance performance of athletes. We have developed new methods to detect the misuse of artificial blood, and I think this is not a problem any longer. Another thing which is also used to increase the red blood cells and to increase oxygen transport capacity is the use of another peptide hormone such as the erythropoietin, but for this we have now very good methods and we can detect its use very well."

Other substances banned include stimulants, such as amphetamines, ephedrine or strychnine, narcotics like morphine or heroin and cannabinoids, such as hashish or marijuana.

Diuretics, which facilitate the elimination of liquids from the body and can result in rapid weight loss, have also been banned. One of the best known diuretics is furosemide, which has reportedly been used by female gymnasts.